Kerlig is an in-context AI writing assistant designed for macOS that integrates with various AI models such as OpenAI, Claude, Gemini Pro, and Groq, allowing users to enhance their writing directly within any app. It provides spell-checking, grammar correction, and the ability to craft well-composed messages quickly, which can be particularly useful for those who want to avoid typos and communicate effectively without delays. Users can also interact with it as they would with ChatGPT, making it a versatile tool for a wide range of writing and communication tasks. The convenience of having an AI assistant at hand is likely to appeal to professionals, students, and anyone looking to improve their written communication on the Mac platform.